Clutch mechanism having power disengagement

ABSTRACT

A power shift mechanism for causing a clutch to be disengaged by the power of the shaft of the transmission. In other words the mechanism is shifted out of gear under its own power and with little effort on the part of the operator. The mechanism is particularly useful in clutching arrangements for feed rolls of a forage harvester for example, when the rolls become clogged with an excess or slug of material and it is otherwise difficult to shift the clutch out of engagement. The mechanism includes a shifting assembly which first acts to shift a cam means out of the way to a position that permits the shiftable clutching part to be engaged and reverse feed roll direction, and then acts to permit the cam means to cause the shiftable part of the clutch to be forcibly disengaged due to the power of the shaft on which it is splined.

Bite Sttes Fleming CLUTCH MECHANISM HAVING POWER DISENGAGEMENT Philip F.Fleming, West Bend, Wis.

Assignee: Gehl Company, West Bend, Wis.

Filed: Nov. 27, 1970 Appl. No.: 93,063

Inventor:

References Cited UNITED STATES PATENTS 6/1910 Hancock ..192/101 1/1922Reiche1t..... ..192/89 A UX Morris. ..192/89 A X 2,388,407 11/1945Hansen ..192/101 Primary Examiner-Allan D. Hermann Attorney-James E.Nilles [5 7] ABSTRACT A power shift mechanism for causing a clutch to bedisengaged by the power of the shaft of the transmission. In other wordsthe mechanism is shifted out of gear under its own power and with littleeffort on the part of the operator. The mechanism is particularly usefulin clutching arrangements for feed rolls of a forage harvester forexample, when the rolls become clogged with an excess or slug ofmaterial and it is otherwise difficult to shift the clutch out ofengagement. The mechanism includes a shifting assembly which first actsto shift a cam means out of the way to a position that permits theshiftable clutching part to be engaged and reverse feed roll direction,and then acts to permit the cam means to cause the shiftable part of theclutch to be forcibly disengaged due to the power of the shaft on whichit is splined.

4 Claims, 14 Drawing Figures PATENTEDFEBZZ I972 SHEET 1 OF 5 FIG. 10

FIG.9

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Y= Z FIG. 1 3 ATTORNEY mimwrwzz 1912 3.643 767 sum 2 UF 5 v INVENTOR=PHILIP F'. FLEMING BY: W

/ ATTORNEY PATENTEBFEBZZ I912 SHEET 3 OF 5 FIG. 5

INVENTOR:

PHILIP F. FLEMING BY= ATTORNEY PATENTEDFEB22 I972 SHEET 6 0F 5 INVENTOR=PHILIP F. FLEMING ATTORNEY PATENTEDFEBZZ I912 3.648 767 SHHT 5 UF 5INVENTOR= PHILIP E FLEMING BY= i AT TOR NEY CLUTCH MECHANISM HAVINGPOWER DISENGAGEMENT BACKGROUND OF THE INVENTION In forage harvesters orthe like where the feed rolls must be frequently disengaged in order topermit slugs of material to clear themselves in the chopping cylinderbefore continued intake of the crop material, it has been conventionalpractice to provide clutches having a part shifted by the movement of anoperators lever. Heretofore however, when the feed rolls became jammedwith a slug of material, it was very difficult for the operator toforcibly cause the shiftable clutch part to move out of engagement.

SUMMARY OF THE PRESENT INVENTION The present invention provides ashifting mechanism which utilizes the power of the shaft being driven toforcibly cause shifting of one of the clutch parts and consequentlydisengaging the clutch. The arrangement is such that the operator of thevehicle, such as a forage harvester having feed rolls that are to beclutchable to the power drive, can manually engage the clutch so as tocommence feed roll action and this usually requires no great effort onthe part of the operator. However, when the feed rolls become jammedwith a slug of material, the mechanism of the present invention includesmeans shiftable by the operator, which means permits a cam on thecarrier to come into engagement with the power driven clutch member,thereby causing the clutch member to shift and be disengaged under theinfluence of the power driven shaft. In other words, the rotation of thepower driven shaft causes the shiftable clutch member to ride up on thecam, thereby axially separating the adjacent clutch jaws and disengagingthe clutch.

These and other objects and advantages of the present invention willappear hereinafter as this disclosure progress, reference being had tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of aforage harvester embodying the present invention, certain parts beingshown as broken away or removed for the sake of clarity;

FIG. 2 is a cross-sectional plan view of the transmission shown in FIG.1 and taken generally along the line 2-2 in that view, but on anenlarged scale;

FIG. 3 is a cross section, fragmentary view of a portion of the deviceshown in FIG. 2, but showing the sliding clutch when being shifted intoengagement with the jaws of the reverse gear;

FIG. 4 is a fragmentary, plan view of the sliding clutch shown in FIG. 3when it is about to be engaged by the spring loaded cam carrier;

FIG. 5 is a perspective, exploded view of the shiftable clutch mechanismof the present invention, some parts being shown as broken away forclarity;

FIG. 6 is a transverse, sectional view taken generally along the line6-6 in FIG. 2, but on a reduced scale;

FIG. 7 is a transverse sectional view taken generally along the line 77in FIG. 2;

FIG. 8 is a sectional view taken along the line 8-8 in FIG.

FIG. 9 is an end elevational view of the sliding clutch shown in FIG.10;

FIG. 10 is a front elevational view of the sliding clutch;

FIG. 1 l is an end elevational view of the sliding clutch taken from theopposite end from the FIG. 9 showing;

FIG. 12 is a fragmentary side view of the reverse gear jaw which engageswith the sliding clutchjaws shown in FIG. 9;

FIG. 13 is a fragmentary side view of the forward gear jaw which engagesthe sliding clutch jaws shown in FIG. I1; and

FIG. 14 is a schematic, spread out view of the power transmission.

DESCRIPTION OF A PREFERRED EMBODIMENT The invention has been shown inFIG. I as used in connection with a forage harvester H of the type thatis adapted to be pulled by its forwardly extending frame F by a tractivevehicle. The harvester includes a lower feed roll LF and an upper feedroll UF which are rotatably driven so as to receive the crop from thefield which is delivered to it by the pickup attachment (not shown). Thecrop passes through both the feed rolls, the latter of which feed thecrop to a chopping cylinder (not shown), and from which the choppedmaterial is then delivered by the spout 2 to a trailing wagon or thelike (not shown).

The two feed rolls rotate in a direction towards one another at theiradjacent peripheries so that the material passes between the rolls. Theamount of material delivered to the rolls varies and sometimes a slug ofparticularly heavy mass of material is engaged between the rolls. Underthese circumstances, it is often necessary to shift the drive mechanismwhich drives the rolls out of engagement so that the machine can clearitself of these heavy slugs before additional crop material is fed tothe chopping cylinder.

Heretofore it has been a difiicult task for the operator to shift therolls out of engagement, that is to declutch the rolls when they werejammed with excess material, and the present invention provides atransmission that is declutched under power of the unit itself when itis desired to stop the feed rolls.

The transmission housing 5 is mounted on the frame of the harvester andan endless chain 7 delivers power to an input sprocket 10 which extendsfrom the housing 5. Chain 7 is driven from the power takeoff shaft (notshown) that in turn is driven by the tractor in the conventional manner.The power input sprocket 10 is fixed to ashort stub shaft 11 journaledin the housing and shaft 11 has a smaller gear 12 fixed to it. Gear 12is in constant mesh with a larger gear 13 which in turn is fixed to atransmission shaft 14 journaled in the housing. A pair of gears 15 and16 are also fixed to shaft 14. Gear 15 is in constant mesh with a largerforward gear F that rotates freely on a clutch shaft 20 that extendsthrough the housing and outwardly from both sides thereof. Gear 16 is inconstant mesh with a reverse idler 17 which is mounted on shaft 18supported by the housing. The reverse idler 17 is then in constant meshwith a larger reverse gear R that is freely journaled on the clutchshaft 20.

With the transmission thus far described, input power gear means areprovided for transmitting power to continuously rotate both the forwardgear F and the reverse gear R, in opposite directions, the gears F and Rbeing freely journaled on the clutch shaft 20.

, The gears F and R have clutch jaws located on their inner sides, asshown in FIGS. 12 and 13. The clutch member C has jaws on each ofitsaxial ends for engagement with the jaws of the reverse gear R or theforward gear F, and this clutch and its jaws are clearly shown in FIGS.9, l0 and II. This axially shiftable clutch member C is splined to shaft20 and can be shifted either into engagement with the jaws of gear R orgear F, to cause respectively, reverse or forward rotation of shaft 20.

Power is then transmitted from the clutch shaft 20 to the upper andlower feed rolls as follows. A gear 21 is fixed to shaft 20 on theoutside of the housing and is in constant mesh with another gear 22 thatis fixed to shaft 23 that extends through the housing. Another gear 24is fixed to shaft 23 and it is in constant mesh with still another gear25 that is fixed to shaft 26 journaled in the housing. Thus, shafts 23and 26, respectively drive the lower and upper feed rolls, and theserolls can be reversed in their direction of feed by engagement of theclutch member C with either the reverse gear R or forward gear F. Themeans for engaging the clutch member C with either of the gears R or Fwill now be described.

As shown in FIG. 1, an operators rod 40 extends forwardly to within easyreach of the operator when he is situated on the tractive vehicle. Bypulling this rod 40, the arm 42 is swung to rotate a vertically disposedshifter rod 43. The rod 43 is journaled adjacent its upper and lowerends in the housing H as shown in FIG. 8. A pair of vertically spacedwing plates 44 and 45 are fixed as by welding to the rod 43, as shown inFIG. 5, and rotate with the rod as the latter is actuated by theoperator. The free ends of these plates have an arcuate slot 44a and 450formed therein to form fork tines which engage the trunnion pins 48 orthe shifter yoke 49. The wing plates also have a rounded corner 50 and51 at their rear corners.

The clutch C is shown in the neutral position in FIG. 2 and is shown asbeing shifted to engage the reverse gear R in FIG. 3. The operation ofthe clutch in shifting from the neutral position shown in FIG. 2 to thereversing direction shown in FIG. 3 will now be described.

A pair of cam carriers 61 and 61a are provided for the reverse gear andits clutch jaws and for the forward gear and its clutch jaws.respectively. As the structure and operation of the carriers is thesame, only one will be described in detail.

Referring to FIGS. 2 and 3, during the initial shifting movement of theshifter assembly which is comprised of rod 43 and wing plates 44 and 45,the shoulders 50 of the plates first act to engage a flange 60 of thecam carrier 61. The earn carrier is fabricated from heavy sheet steeland has an elongated aperture 62 generally centrally located therein,and the carrier also has a smaller slot 62a which merges with theaperture 62. This cam carrier also has a cam member 63 welded theretoand which includes a cam surface 64 having a low end 65 and a high end66, in an axial direction. As will appear, this cam surface is slideableinto engagement with the adjacent jaws of the clutch member C. Theopening 62 is also elongated in a transverse direction so that the camcarrier 61 can slide transversely over the periphery of the hub 67 ofthe gear R.

An anchor shaft 70 is fixed in the lugs 71 formed integral with theinterior of the housing, and a pair of torsion springs 73 and 74 aremounted on shaft 70 and the ends of these springs extend throughapertures 77 of brackets 78 which are welded to the inner surface of thecam carrier. Recesses or slots 62a of the cam carriers surround theshaft 70 and help guide the cam in its transverse sliding movement. Thesprings 73, 74 act to bias the cam carrier to a position in which thecam 63 is held against the hub 67 of the gear R, that is against theoutside diameter of the gear jawsv The opening 62 of the carrier is ofsuch a size that it nests over the hub 67 of the reverse gear and thecarrier lies against the inner face 68 of the gear. The hub of theclutch member C however, is slightly larger than the diameter of the hub67 of the gear. The cam surface 64 is so shaped that it complements theradial slope of the jaws of the sliding clutch C. Conscquently, there isa rotational position of the engaged gear and the sliding clutch atwhich the cam will axially nest between the gear face 68 and the slopingjaws of the sliding clutch, the jaws of the gear being of a smallerdiameter than the jaws of the sliding clutch. The rotation of theengaged gear and clutch causes the jaws of the sliding clutch to climbthe cam surface 64 of the cam 63, and consequently forces the slidingclutch C axially away from the gear R thereby providing disengagement ofthe jaws of the clutch. Thus there is a power shifting due to thedriving effect of shaft 20, of the clutch to the disengaged position.

In the neutral position, both cams 63 bear against the periphery of thehub of their respective gears. In other words, they bear against theperiphery of the gear jaws and at the same time bear against the roundedcorners 50, 51 of the wing plates of the shifter assembly. The slidingclutch C and yoke 49 assume a disengaged position while the springloaded handle and shifter fork are in the centrally located detentposition. Rotation of the shifter assembly by the operator in aclockwise direction places the parts in the position indicated in FIG.3. The wing plate of the shifter fork has shifted the cam which has beenlaying against the gear away from the shaft. In this condition, thesliding clutch C can engage with gear R. Clearance is built into thecentral groove 80 of the sliding clutch, which groove receives thetrunnioned yoke and clearance is also in the fork tines which actuatethe yokev This clearance assures that the cam will be moved out of theway by rotation of the fork before the sliding clutch C is moved axiallyinto place. In other words, the initial movement of the shifter assemblycauses the cam to radially shift out of the way of the clutch.

The manual control rod 42 (FIG. 1) is held in this position against thespring 82 connected to it for as long a period as the reverse conditionof the rolls is required, and this is generally a matter of seconds.When the control handle is released by the operator, the spring 82returns the detent to the neutral position. The torsion spring 74 holdsthe cam plate against the then retreating wing plates of the shifterfork until the cam 63 contacts the periphery of the sliding clutch jaws.Since these are rotating, the nesting position will occur in no morethan one-half revolution at which time the cam 63 will slip into contactwith the jaws of the clutch and disengage the clutch as above indicated.It is noted that the clearance in the sliding clutch groove and the forktines permits the shifter fork and cam to rotate into place withoutcontacting the sliding clutch thereby relieving the operator of thenecessity for mechanical disengagement.

The operation of the clutch from neutral to the forward direction ofrotation is the opposite of that above described and the action betweenthe forward cam plate and the forward gear is as above described.

RESUME The clutch mechanism provided by the present invention includes aclutch shaft having a pair of continuously and oppositely rotating gearsfreely journaled thereon, and also has an axially shiftable clutchmember splined to the shaft for rotation therewith and for selectiveengagement with either one of the oppositely rotating gears. A cam meansincluding a cam carrier is provided between the shiftable clutch memberand each of the gears and this carrier has a cam for engagement with theadjacent jaws of the shiftable clutch member. The carrier is slideableover the hub of its associated gear, which gear hub is of a smallerdiameter than the hub of the clutch member. Shifting means are providedfor first shifting the cam carrier out of the way of the shiftableclutch member and then the clutch member is shifted into engagement withthe gear. After a short period of engagement in which the feed rolls arereversed, the operator releases his control lever and this permits thespring biased cam carrier to return to its original position. In thisposition, the cam of the cam carrier is engaged by the power drivenclutch member which forcibly causes the axial movement of the clutchmember to the disengaged position.

Thus, the present invention provides a means for power shifting theclutch into the disengaged position.

The invention finds particular utility in a forage harvester where feedrolls or other attachments of the machine, such as a mower sickle orcorn harvesting head must be stopped periodically during the cropfeeding operation in order to prevent an excess slug of crop fromoverloading the machine. Under these conditions, the jaws of the slidingclutch are transmitting high torque. To manually disengage the clutch inthis condition is very difficult and requires linkages of impracticaldesigns. The present invention provides power means for disengaging theclutch under any power transmitting condi tion.

Iclaim:

1. Power disengaging clutch mechanism comprising, a clutch shaftjournaled for rotation in either direction, a clutch member splined tosaid shaft for axially shifting thereon and having clutchjaws on eachaxial end, a forward gear rotatably journaled on said shaft at one endof said clutch member and havingjaws for engagement with said member, areverse gear rotatably journaled on said shaft and having jaws forengagement with said member, input power means for continuously rotatingsaid forward gear and said reverse gear in the opposite directions,output shaft means mounted in said housing, gear means connected betweensaid clutch shaft and said output shaft means for causing rotationthereof, cam means slideably mounted relative to and adjacent each endof said clutch member, said cam means being shiftable out of engagingalignment with the jaws of said gears and also shiftable into engagingalignment with the jaws of the adjacent gear, and shifting means forselectively shifting said cam means and also for axially shifting saidclutch member, said shifting means engaging and shifting a selected cammeans to said nonengaging alignment prior to the axial shifting of saidclutch member into engagement with the gear adjacent said selected cammeans, and means for returning said selected cam means to said engagingalignment with said clutch member to positively shift the latter in anaxial direction out of engagement with said gear.

2. Clutch mechanism comprising, a housing, a clutch shaft journaled insaid housing for rotation in either direction, a clutch member splinedto said shaft for axially shifting thereon in opposite directions andhaving clutch jaws adjacent each axial end thereof, a forward gearrotatably journaled on said shaft at one end of said clutch member andhaving jaws for engagement with the adjacent jaws of said member, areverse gear rotatablyjournaled on said shaft at the other end of saidclutch member and having jaws for engagement with the adjacent jaws ofsaid member, input power gear means for continuously rotating saidforward gear in one direction and said reverse gear in the oppositedirection, output shaft means mounted in said housing, gear meansconnected between said clutch shaft and said output shaft means forcausing rotation thereof; a pair of cam carriers and each including acam, one carrier slideably mounted adjacent each end of said clutchmember between a first position in which their cams are out of engagingalignment with the jaws of the gears and a second position in whichtheir cams are engagingly aligned with the jaws of their respectiveadjacent gear; shifting means for selectively shifting said carriers andalso for axially shifting said clutch member in opposite directions,said shifting means having a portion engaging and shifting a selectedcarrier to said first position prior to the axial shifting of saidclutch member into engagement with the gear adjacent said selectedcarrier, and means for returning said selected carrier to said secondengaging position as said shifting means is returned to a neutralposition, whereby said clutch member engages the cam of said selectedcarrier and is positively shifted in an axial direction and out ofengagement with said gear due to the rotation of said clutch memberagainst said cam.

3. Clutch mechanism comprising, a housing, a clutch shaft journaled insaid housing for rotation in either direction, a clutch member splinedto said shaft for axially shifting thereon in opposite directions, saidmember having clutch jaws on each axial end thereof, a forward gearrotatably journaled on said shaft at one end of said clutch member andhaving jaws on its side' adjacent said member for engagement with theadjacent jaws of said member, a reverse gear rotatably journaled on saidshaft at the other end of said clutch member and having jaws on its sideadjacent said member for engagement with the adjacent jaws of saidmember, input power gear means for continuously rotating said forwardgear in one direction and said reverse gear in the opposite direction, apair of output shafts mounted in said housing and extending therefrom,gear means connected between said clutch shaft and at least one of riersin a transverse direction and also for axially shifting said clutchmember in opposite directions, said shifting means hav ing a portionengaging a selected carrier and shifting said carrier to said firstposition prior to the axial shifting of said clutch member intoengagement with the gear adjacent said selected carrier, and means forreturning said selected carrier to said second engaging position as saidshifting means is returned to a neutral position, whereby said clutchmember engages the cam of said selected carrier and is positivelyshifted in an axial direction and out of engagement with said gear dueto the rotation of said clutch member against said cam.

4. In a forage harvester having a pair of oppositely rotating feedrolls, clutch mechanism comprising, a housing on said harvester, aclutch shaft journaled in said housing for rotation in either direction,a clutch member splined to said shaft for axially shifting thereon inopposite directions, said member having clutch jaws on each axial endthereof, a forward gear rotatably journaled on said shaft at one end ofsaid clutch member and having jaws on its side adjacent said member forengagement with the adjacent jaws of said member, a reverse gearrotatably journaled on said shaft at the other end of said clutch memberand having jaws on its side adjacent said member for engagement with theadjacent jaws of said member, input power gear means for continuouslyrotating said forward gear in one direction and said reverse gear in theopposite direction, a pair of output shafts mounted in said housing andextending therefrom and having means for connection to said feed rolls,gear means connected between said clutch shaft and at least one of saidoutput shafts for causing rotation thereof, a pair of cam carriers andeach including a cam, one carrier slideably mounted at each end of saidclutch member and between the clutch member and the forward and reversegears, said carriers being shiftable between a first position in whichtheir cams are out of engaging alignment with the jaws of theirrespective adjacent gear and a second position in which their cams areengagingly aligned with the jaws of their respective adjacent gear,shifting means for selectively shifting said carriers in a transversedirection and also for axially shifting said clutch member in oppositedirections, said shifting means having a portion engaging a selectedcarrier and shifting said carrier to said first position prior to theaxial shifting of said clutch member into engagement with the gearadjacent said selected carrier, means for returning said selectedcarrier to said second engaging position as said shifting means isreturned to a neutral position, whereby said clutch member engages thecam of said selected carrier and is positively shifted in an axialdirection and out of engagement with said gear due to the rotation ofsaid clutch member against said cam; an operators lever on saidharvester and connected to said shifting means for shifting the latterin either direction to cause engagement of either of said reverse orforward gears; and means for returning said lever to a neutral position.

1. Power disengaging clutch mechanism comprising, a clutch shaftjournaled for rotation in either direction, a clutch member splined tosaid shaft for axially shifting thereon and having clutch jaws on eachaxial end, a forward gear rotatably journaled on said shaft at one endof said clutch member and having jaws for engagement with said member, areverse gear rotatably journaled on said shaft and having jaws forengagement with said member, input power means for continuously rotatingsaid forward gear and said reverse gear in the opposite directions,output shaft means mounted in said housing, gear means connected betweensaid clutch shaft and said output shaft means for causing rotationthereof, cam means slideably mounted relative to and adjacent each endof said clutch member, said cam means being shiftable out of engagingalignment with the jaws of said gears and also shiftable into engagingalignment with the jaws of the adjacent gear, and shifting means forselectively shifting said cam means and also for axially shifting saidclutch member, said shifting means engaging and shifting a selected cammeans to said nonengaging alignment prior to the axial shifting of saidclutch member into engagement with the gear adjacent said selected cammeans, and means for returning said selected cam means to said engagingalignment with said clutch member to positively shift the latter in anaxial direction out of engagement with said gear.
 2. Clutch mechanismcomprising, a housing, a clutch shaft journaled in said housing forrotation in either direction, a clutch member splined to said shaft foraxially shifting thereon in opposite directions and having clutch jawsadjacent each axial end thereof, a forward gear rotatably journaled onsaid shaft at one end of said clutch member and having jaws forengagement with the adjacent jaws of said member, a reverse gearrotatably journaled on said shaft at the other end of said clutch memberand having jaws for engagement with the adjacent jaws of said member,input power gear means for continuously rotating said forward gear inone direction and said reverse gear in the opposite direction, outputshaft means mounted in said housing, gear means connected between saidclutch shaft and said output shaft means for causing rotation thereof; apair of cam carriers and each including a cam, one carrier slideablymounted adjacent each end of said clutch member between a first positionin which their cams are out of engaging alignment with the jaws of thegears and a second position in which their cams are engagingly alignedwith the jaws of their respective adjacent gear; shifting means forselectively shifting said carriers and also for axially shifting saidclutch member in opposite directions, said shifting means having aportion engaging and shifting a selected carrier to said first positionprior to the axial shifting of said clutch member into engAgement withthe gear adjacent said selected carrier, and means for returning saidselected carrier to said second engaging position as said shifting meansis returned to a neutral position, whereby said clutch member engagesthe cam of said selected carrier and is positively shifted in an axialdirection and out of engagement with said gear due to the rotation ofsaid clutch member against said cam.
 3. Clutch mechanism comprising, ahousing, a clutch shaft journaled in said housing for rotation in eitherdirection, a clutch member splined to said shaft for axially shiftingthereon in opposite directions, said member having clutch jaws on eachaxial end thereof, a forward gear rotatably journaled on said shaft atone end of said clutch member and having jaws on its side adjacent saidmember for engagement with the adjacent jaws of said member, a reversegear rotatably journaled on said shaft at the other end of said clutchmember and having jaws on its side adjacent said member for engagementwith the adjacent jaws of said member, input power gear means forcontinuously rotating said forward gear in one direction and saidreverse gear in the opposite direction, a pair of output shafts mountedin said housing and extending therefrom, gear means connected betweensaid clutch shaft and at least one of said output shafts for causingrotation thereof, a pair of cam carriers and each including a cam, onecarrier slideably mounted at each end of said clutch member and betweenthe clutch member and the forward and reverse gears, said carriers beingshiftable between a first position in which their cams are out ofengaging alignment with the jaws of their respective adjacent gear and asecond position in which their cams are engagingly aligned with the jawsof their respective adjacent gear, shifting means for selectivelyshifting said carriers in a transverse direction and also for axiallyshifting said clutch member in opposite directions, said shifting meanshaving a portion engaging a selected carrier and shifting said carrierto said first position prior to the axial shifting of said clutch memberinto engagement with the gear adjacent said selected carrier, and meansfor returning said selected carrier to said second engaging position assaid shifting means is returned to a neutral position, whereby saidclutch member engages the cam of said selected carrier and is positivelyshifted in an axial direction and out of engagement with said gear dueto the rotation of said clutch member against said cam.
 4. In a forageharvester having a pair of oppositely rotating feed rolls, clutchmechanism comprising, a housing on said harvester, a clutch shaftjournaled in said housing for rotation in either direction, a clutchmember splined to said shaft for axially shifting thereon in oppositedirections, said member having clutch jaws on each axial end thereof, aforward gear rotatably journaled on said shaft at one end of said clutchmember and having jaws on its side adjacent said member for engagementwith the adjacent jaws of said member, a reverse gear rotatablyjournaled on said shaft at the other end of said clutch member andhaving jaws on its side adjacent said member for engagement with theadjacent jaws of said member, input power gear means for continuouslyrotating said forward gear in one direction and said reverse gear in theopposite direction, a pair of output shafts mounted in said housing andextending therefrom and having means for connection to said feed rolls,gear means connected between said clutch shaft and at least one of saidoutput shafts for causing rotation thereof, a pair of cam carriers andeach including a cam, one carrier slideably mounted at each end of saidclutch member and between the clutch member and the forward and reversegears, said carriers being shiftable between a first position in whichtheir cams are out of engaging alignment with the jaws of theirrespective adjacent gear and a second position in which their cams areengagingly aligned with tHe jaws of their respective adjacent gear,shifting means for selectively shifting said carriers in a transversedirection and also for axially shifting said clutch member in oppositedirections, said shifting means having a portion engaging a selectedcarrier and shifting said carrier to said first position prior to theaxial shifting of said clutch member into engagement with the gearadjacent said selected carrier, means for returning said selectedcarrier to said second engaging position as said shifting means isreturned to a neutral position, whereby said clutch member engages thecam of said selected carrier and is positively shifted in an axialdirection and out of engagement with said gear due to the rotation ofsaid clutch member against said cam; an operator''s lever on saidharvester and connected to said shifting means for shifting the latterin either direction to cause engagement of either of said reverse orforward gears; and means for returning said lever to a neutral position.